Updated man pages
New protocol version 2

- changes to 'strings' and 'dictionary' encoding
- tracking new capabilities of zproto codec generator
- meant to remove limits on sizes of these fields
- documented by RFC 36
- aimed at eventual Zyre v1.0 release
Problem: ENTER ipaddress field is ambiguous

- does not help when you have multiple nodes on same machine

Solution: add port to ipaddress

- now returns ipaddress:port string in ENTER
Merge pull request #157 from hintjens/master

New protocol version 2